In this paper, the authors propose a Hadoop-based Distributed Video Transcoding System in a cloud computing environment that transcodes various video codec formats into the MPEG-4 video format. This system provides various types of video content to heterogeneous devices such as smart phones, personal computers, television, and pads. They design and implement the system using the MapReduce framework, which runs on a Hadoop Distributed File System platform, and the media processing library Xuggler. Thus, the encoding time to transcode large amounts of video content is exponentially reduced, facilitating a transcoding function. For performance evaluation, they focus on measuring the total time to transcode a data set into a target data set for three sets of experiments.